Betta fish cannot survive in completely oxygen-free environments. However, thanks to their unique Labyrinth Organ, they can live for extended periods in water with low oxygen levels or temporary oxygen depletion. Below is a detailed analysis of the betta fish's living environment:
The Function of the Labyrinth Organ
Betta fish possess a specialized respiratory structure known as the Labyrinth Organ, which allows them to breathe oxygen directly from the air. This adaptation gives bettas a stronger survival advantage in low-oxygen or temporarily oxygen-poor water, as they can surface to obtain the oxygen they need.
Oxygen Conditions in Natural Habitats
Betta fish are native to environments like rice paddies, swamps, and shallow, slow-moving waters in Southeast Asia. These habitats typically have slightly acidic water, slow water flow, and oxygen levels that are not always sufficient. Nevertheless, bettas thrive in these settings by relying on their Labyrinth Organ.
Oxygen Requirements in Artificial Cultivation
Recommended Dissolved Oxygen Level: For captive bettas to stay healthy and in good condition, the dissolved oxygen (DO) level in the water should ideally be maintained at around 5 mg/L. This concentration ensures bettas receive enough oxygen to meet their physiological needs.
Risks of Oxygen Depletion: While bettas can tolerate low-oxygen environments, extremely low DO levels—often caused by overstocking, high water temperatures, or poor water circulation—can lead to oxygen deficiency symptoms. These symptoms include gasping at the water surface, rapid breathing, and abnormal swimming behavior. In severe cases, oxygen depletion can even be life-threatening for bettas.
Aeration Recommendations: In environments with high stocking densities or elevated water temperatures, proper aeration (e.g., using air stones or power filters) is recommended to maintain adequate oxygen levels. Additionally, regular water changes are a crucial practice for keeping the water clean and preserving healthy oxygen content.
Special Oxygen Needs in Specific Stages
Fry Rearing Stage: When raising betta fry (young fish), the water requires a higher oxygen level—at least 6 mg/L—to support their normal growth and development.
Gill Development Stage: During the period when betta juveniles are still developing their gills, they cannot rely on atmospheric oxygen as fully as adult bettas. Therefore, it is essential to increase the dissolved oxygen level in the water during this phase.